Envenomations: Bees, Snakes and Spiders Jeff Hurley MD Emergency Medicine Department Martin Luther King.

Envenomations:Bees, Snakes and Spiders

Jeff Hurley MD

Emergency Medicine Department

Martin Luther King

Objectives

Epidemiology Pathophysiology Treatment …of bees, snakes and spiders.

Hymenoptera

Hymenoptera

More deaths than any other envenomation. Includes: bees, wasps, hornets, yellow

jackets, and ants Incidence of approximately 1 million a year. Vast majority (17-56%) only minor reactions. Generalized reactions in 1-2%. Only about 5% seek medical care. Approximately 30-120 deaths annually. Social creatures…attack when disturbed.

Pathophysiology

Allergic reaction mediated by IgE. Prior exposure to venom proteins

Venom load (histamine, bradykinin, dopamine, serotonin, mast cell degranulating peptide) 30 vespid stings 200 honeybee stings

Reaction: Urticaria Vasodilation Bronchospasm Laryngospasm Angioedema

Hypersensitivity

Pathophysiology

Rapid onset of symptoms. 50% of deaths in the first 30 minutes 75% in the first 4 hours

Distinguish local versus generalized reactions. Local: pain, edema, pruritis, nausea and vomiting

may also occur without generalization. Generalized: urticaria, confluent rash, shortness of

breath, wheezing, weakness, edema, anxiety, chest pain.

Reactions

Prehospital

Immediate treatment may be life-saving. Manage generalized reactions similar to anaphylaxis EVEN IN THE ABSENSE OF SHOCK. Remove Stinger (pinching and traction is acceptable) Airway prn Breathing treatments: albuterol Cardiovascular collapse: fluid bolus and epinephrine Antihistamines Apply Ice Elevate Extremity

Local reactions may be life threatening if swelling in proximal to airway.

Treatment• Antihistamines

– Diphenhydramine: Drug of choice. H1 and partial H2 blockade. • Adult: 50-75 mg PO/IM Q4• Pediatric: 1-2 mg/kg PO/IM

– Cimetidine: Indicated for systemic reactions that do not respond completely to diphenhydramine.

• Adult: 300-800 mg IV Q6• Pediatric: 5 mg/kg IV Q6

• Epinephrine: Drug of Choice for systemic reactions.– Alpha agonist effects: reverse hypotension, vasodilation, vascular permeability– Beta agonist effects: causes bronchodilation, increased cardiac output

• Adult: 0.2 to 1 mg IV/SC• Pediatric: 0.01 to 0.1 mg/kg IV/SC

– Caution in older people with CAD, DM, HTN, CVA Hx, BPH. Rapid IV infusion may cause MI, hemorrhagic CVA, cardiac arrhythmias.

• Albuterol• Steroids (solumedrol): Generalized reactions. Decrease PMN activity and

capillary permeability.– Adults: 250 mg to 1 gm Q6– Pediatric: 0.2 to 2 mg/kg IV Q6

• Theophylline: Relieve bronchospasm in resistant cases.

Complications

Infection: Especially in young children. Rebound Anaphylaxis Cross-over reactivity Serum-sickness reaction

6-14 days s/p sting ASA, Benedryl, Prednisone Complications: vasculitis, neuropathy,

glomerulonephritis, shock and death.

Medical / Legal

Failure to remove stinger Failure to observe Failure to educate and discharge with epi-pen. Failure to refer to allergist.

Snakes

Snakes

Colubridae: 70% of snakes: nonvenomous except two species

Hydrophidae: sea snake Neurotoxic

Elapidae: Coral snake and Cobra Neurotoxic

Crotalidae: Pit Viper: rattlesnakes, moccasins, copperheads Hemotoxic >>> Neurotoxic 98% of envenomations in the US

Epidemiology

Incidence greatest in Southern US. 97% on extremities: 2/3 on upper and 1/3 on

lower. Males 9X than females. Young adults. Approx. 7000 bites reported annually. Rattlesnakes 2/3 of all bites. Dry bite (no venom): 30-50% 5.5 Deaths average annually.

Venomous vs. Non-Venomous

“Red on Yellow, Kill a Fellow”

“Red and Black, Venom Lack”

Pathophysiology

Venom is composed of either neurotoxin or hemotoxin. Proteins: Cause coagulation, anticoagulation,

hemorrhage, hemolysis, myonecrosis. Polypeptides: Target heart, lungs, kidney, synapses. Variable delivery of toxin.

Clinical: Local envenomation can lead to DIC, pulmonary edema, shock. Anaphylactic reactions secondary to VAPs.

Can occur slowly from mild pain to multisystem organ failure.

Elapidae

Coral and Cobra snakes. Venom blocks neuromuscular transmission, and has direct

effects on the heart and muscles. Signs and Symptoms include:

Minor pain at area of bite. Local painful paresthsias Mild STS AMS Cranial Nerve dysfunction

Ptosis is common and may be the first sign of envenomation. Respiratory distress and cyanosis

Onset may be delayed 10-12 hours but may progress rapidly thereafter.

Respiratory failure is the usual cause of death.

Crotalidae

Rattlesnakes, moccasins, copperheads Pain immediately after bite. Severity related to dose to venom. Progressive subcutaneous edema. Possibility for a compartment

syndrome, but it has not been described. Possible need for fasciotomy. Recommended to monitor cap refill as it may be difficult to distinguish between compartment syndrome and the effects of the envenomation.

Petechiae, eccyhmosis, bullae (serous and hemorrhagic). Death related to failure of coagulation and increased capillary

membrane permeability. Pulmonary edema, shock and death follow. Allergic reactions may occur as well. Labs: CBC/Platelets, PT/PTT, fibrinogen, FSP, type and cross, UA Rhabdomyolysis: total CK, electrolytes, (EKG)

Grading Envenomation - Crotalidae

• Grade 0: no evidence of envenomation (< 1 inch)

• Grade I: 1-5 inches of edema and erythema

• Grade II: moderate envenomation, severe widely distributed pain, petechiae, eccyhmosis

• Grade III: spread within 12 hours to entire extremity and trunk, systemic manifestations, tachycardia, hypotension, temperature abnormalities

• Grade IV: very severe, swelling of extremity and trunk within a few hours, systemic within 15 minutes, convulsions, coma, death may occur

Reactions

Prehospital All snakebites should be considered emergencies

especially in the first 6-8 hours. ABCs Remove clothing. Spread of venom should be slowed.

Immobilize bitten area. NPO Constricting band that impedes venous flow but not arterial

flow If patient is seen in 15 minutes, suction can be

performed to remove venom. Sawyer Extractor (mouth suction is contraindicated) No benefit has been demonstrated, and additional damage

may be inflicted. Ice is not helpful in slowing the spread of venom, but

does help with pain control. If capable, identify the snake, or transport the dead

snake. (avoid touching the head, as envenomizations may occur)

Cardiac Monitor, IV fluids (2), pain control. Arizona Poison Control (520-626-6016)

Treatment

Supportive: IVF, pain control, antihistamines

Antibiotics, tetanus Elapidae: Intubation prn, do not use

gradation scale Crotalidae: DIC may require FFP Antivenin

Elapidae

Epinephrine if hypotensive despite fluid administration Consider dopamine and levophed Micrurus fulvius Antivenin

Give 3-6 vials IV over 1-2 h, if signs or symptoms continue to progress, add 3-5 vials over 1-2 h Read package insert Slow IV infusion that increases rate Similar to IVIG protocols

rarely, more than 10 vials are required Before administration, the patient's IV volume should be

expanded using crystalloid solutions Pretreat with antihistamines, diphenhydramine +/- cimetidine Skin testing prior to giving antivenin Horse-based antivenin. Possibility of anaphylactic shock.

Crotalidae

Can use severity table to aid in decision to use. Old horse based polyvalent Crotalidae antivenin.

Moderate envenomation: 5-10 vials Severe envenomation: 15-20 vials Premedication with diphenhydramine. Pretreatment with epinephrine 0.25 mg SC Monitor for anaphylactic reaction.

New Fab antigen binding fragments from ovine (sheep). Fewer allergic reactions. Similar to Digibind Fab. Pretesting is not required

Spiders

Spiders

Only spiders to be feared are the Black Widow and the Brown Recluse. Other spiders simply cause pain.

Incidence is unknown. Bites rarely cause death…less than 1%.

Children more vulnerable. Older patients with CAD also at risk.

13,000 reported bites with 1,300 described as severe.

Black Widow – Lactrodectus

Bites only when disturbed. Neurotoxin released that causes localized pain that may be

followed by muscle cramps, abdominal pain, weakness, tremor, headache, anxiety, and insomnia. Reactions may take 15 minutes to 6 hours to develop.

Severe bites can cause nausea, vomiting, dizziness, chest pain, and respiratory difficulties.

Abdominal pain mimic acute abdomen, colic, or food poisoning.

Little local damage to tissues. Fang marks. Patients experience immediate pain. Possible metallic taste in mouth. Side effect of hypertension and tachycardia.

Treatment

Pain control: Demerol as it may produce less smooth muscle spasm. Calcium Gluconate: Mechanism unknown. Controversial.

Normalizes nerve and cardiac function. 1-2 ml/kg of 10% solution as slow IV, not to exceed 10 ml Contraindications: dig toxicity, renal or cardiac disease

Latrodectus Antivenin: Neurtalizes the toxin. Produces rapid relief of pain. Some recommend usage only in children, elderly or those with

underlying medical problems. 2.5 ml IM in anterolateral thigh Or diluted in 10-50 cc NS and infused IV over 15 minutes in severe

cases, children less than 12, or in cases of shock. Same dose in children as adults. Horse serum: potential for anaphylaxis (uncommon…much more likely

with snake antivenins)

Brown Recluse Spider

Loxosceles

Brown Recluse

Distribution in Southern US. Fiddle-back appearance. Severity mild, local, urticarial, to full-

thickness necrosis. Less than 10% of bites result in severe necrosis or systemic manifestations.

Death uncommon. Documented cases affecting children with hemotological problems.

Distribution

History and Physical

BITE IS PAINLESS. Symptoms: Fever, headache, malaise, nausea, vomiting, arthralgia Cutaneous manifestations: macular, papular, petechial eruption. May not be

seen for 6-12 hours after bite. May progress to a necrotic lesion. (less than 10% of the time)

Wounds that do become necrotic, show sgins in 2-3 days. Discoloring occurs with the center purple discolored, an area of blanched skin

do to skin edema, and then erythema surrounding. Characteristic “red, white, and blue” pattern. Significant pain at this stage.

Wounds may take months to heal. Patient with severe reactions show bullae formation, cyanosis, and pain within

6-12 hours. Hemolysis my occur.

Labs to monitor hemolysis: CBC, unconjugated bilirubin, decreased haptoglobin, LDH

UA to monitor for hemoglobinuria

Lesions

Treatment

Virtually all bites heal without treatment in 2-3 months. Clean wound. Ice, elevate, and provide pain medications (anti-inflammatory)

and anti-ich medications (diphenhydramine or atarax). If tissue breakdown occurs, antibiotics are indicated as well as tetanus

prophylaxis. Dapsone may limit tissue damage, but it must be started early. Delay in

starting dapsone may negate its benefits. Believed to supress a halide-myeloperoxidase in PMNs. Adults: 100 mg PO BID x 2 wks Pediatrics: 1-2 mg/kg/day Contraindicated in patients with G6PD deficiency as it may cause hemolysis.

Hyperbaric Oxygen: may speed recovery. Necrotic skin lesions occur in 10% of pts. Surgical care may be instituted but

only after 6-8 wks. Early intervention is not advised. Steroids possibly cause more damage than good. Follow up daily to monitor necrosis. Possible referral to a plastic surgeon.

References

Rosen’s Emergency Medicine, Concepts and Clinical Practice. 2002

eMedicine. www.emedicine.com Merck Manual. www.merck.com Vegas Review

Poisonous?

Pt. complains of rash, joint pain, itching, and muscle aches 10 days after being bitten by a bunch of wasps. What is the cause of her problem?

• A) sensitized lymphocytes causing delayed type hypersensitivity

• B) IgE-mediated release of histamine• C) inflammatory reaction to antigen-antibody

complexes• D) antibody mediated cell lysis• E) G6PD deficiency

Five year old girl (20 kg) bitten by a honeybee five minutes ago complains of wheezing and body rash. Estimated 30 minute transport time. Best treatment choice?

• A) cont. albuterol nebs, antihistamine, IVF

• B) epinephrine 0.2 mg of 1:10,000 SC

• C) epinephrine 2 mg 1:1000 IV

• D) epinephrine 0.2 mg of 1:1,000 SC

• E) epinephrine 0.2 mg 1:10,000 IV

• F) epinephrine 2 mg 1:10,000 SC

No antivenin exists for which envenomation?

• A) Black Widow

• B) Brown Recluse

• C) Coral Snake

• D) King Snake

• E) Rattlesnake

Serum sickness may not be seen in which of the following?

• A) Crotalidae polyvalent antivenin

• B) Horse serum antivenin

• C) Etalidae antivenin

• D) Hymenoptera envonomation

• E) CroFab antivenin